Examplify question bank 1/2 Flashcards
One complication of subarachnoid haemorrhage is blockage of arachnoid granulations. What might the effect of this be?
A. Low intracranial pressure
B. No effect on intracranial pressure
C. Raised intracranial pressure
Raised intracranial pressure
Arachnoid granulations are involved with drainage of CSF. Hence CSF would accumulate and increase the pressure within the skull
Which region on the image of midbrain is the cerebral peduncle?
A. A
B. B
C. C
C. C
Rationale: A is periaqueductal grey matter, B is substantia nigra
A region of white matter is identified in the cord which contains both ascending and descending axons. What is the correct term for this?
A. Fasciculus
B. Funiculus
C. Tract
B. Funiculus
Rationale: A fasciculus is a subdivision of a tract. A tract contains axons travelling in a single direction only (either ascending or descending)
Pure sensory loss in a single dermatome with no associated weakness suggests damage to which structure?
A. Dorsal root
B. Spinal cord
C. Ventral root
A. Dorsal root
Rationale: If the spinal cord ( part within the vertebral column) was damaged this would probably affect multiple dermatomes with associated weakness. If the ventral root was affected there would be weakness with no sensory loss. Dorsal roots contain sensory axons only
Which subdivision of the CNS contains cell bodies and dendrites?
A. Choroid plexus
B. Grey matter
C. White matter
grey matter
Rationale: Choroid plexus makes CSF, white matter contains axons
The thalamus, an important structure in the sensory system, is found in which division of the CNS?
A. Telencephalon
B. Mesencephalon
C. Diencephalon
C. Diencephalon
Rationale: The mesencephalon refers to the midbrain (meso=middle) and the telencephalon refers to the rostral most portions of the brain
Which type of neurone brings information into the central nervous system?
A. Afferent neurones
B. Efferent neurones
C. Interneurones
A. Afferent neurones
Rationale: Efferent neurones carry impulses away from the CNS and interneurones connect afferents and efferents
The hippocampus is found in which lobe of the brain?
A. Frontal lobe
B. Occipital lobe
C. Temporal lobe
Temporal lobe
Rationale: The hippocampus sits infero-medially in the temporal lobe
Which cranial nerve emerges ventrally from the ponto-medullary junction?
A. Abducens nerve
B. Facial nerve
C. Trigeminal nerve
A. Abducens nerve
Rationale: The trigeminal nerve emerges from the lateral aspect of the pons. The facial nerve emerges laterally from the ponto-medullary junction
The superior colliculus is part of which structure?
A. Medulla
B. Midbrain
C. Pons
Midbrain
Rationale: The colliculi sit on the dorsal aspect of the midbrain (and form Mickey mouse’s chin)
A meningomyelocoele contains what?
A. CSF only
B .Spinal cord and CSF
C. Spinal cord but no CSF
B .Spinal cord and CSF
Rationale: Meningo- refers to meninges (and hence CSF) and –myelo refers to the cord. A Meningocoele has only CSF. Cord but no CSF is not possible
The CNS shares an embryological origin with which other tissue?
A. The gut
B. The skin
C. Skeletal muscle
B. The skin
Rationale: CNS is derived from ectoderm, as is skin. Gut derives from endoderm and muscle from mesoderm
Cerebrospinal fluid circulates in which space?
A. The extradural space
B. The subarachnoid space
C. The subdural space
B. The subarachnoid space
Rationale: The extradural space normally contains nothing (but can fill with blood in an extradural haemorrhage). The subdural space contains nothing normally, apart from bridging veins (but can fill with blood in a subdural haemorrhage)
Considering the motor homunculus, which region of the body is represented most laterally in the primary motor cortex?
A. The face
B. The hand
C. The lower limb
A. The face
Rationale: The lower limbs are represented medially and the hand sits in an intermediate position
Which region of cortex sits anterior to the central sulcus?
A. Premotor area
B. Primary motor cortex
C. Primary sensory cortex
B. Primary motor cortex
Rationale: The primary sensory cortex sits posterior to the central sulcus and the premotor area sits anterior to the primary motor cortex
The cuneate fasciculus contains fibres from which body region?
A. C1 - T6
B. T7 - T12
C. L1-L5
C1-T6 (upper body)
Rationale: The gracile fasciculus contains information from the lower half of the body. The head is supplied by a separate system
In the dorsal column, which population of first order fibres ascend most medially?
A. Cervical
B. Thoracic
C. Lumbar
lumbar
A patient has a tumour compressing the left cerebral peduncle. What is the likely effect on the sensory system?
A. Loss of all modalities on the left side
B. Loss of all modalities on the right side
C. Nothing
Nothing
Rationale: For our purposes, the cerebral peduncle contains motor fibres only- ventral. Sensory fibres ascend directly to the thalamus via Mickey mouse’s ‘tears’
remember dorsal= sensory, ventral = motor
A patient has a dorsal column lesion. What is likely to happen if they stand up and close their eyes?
A. Head will turn towards the side of the lesion
B. Nothing
C. They will lose their balance
They will lose their balance
Rationale: Equilibrium relies on having at least 2 out of three inputs to the brain: vision, proprioception and input from the vestibular system. Take two of these away (vision and proprioception in this case) and the patient will lose their balance.
A patient has loss of all sensory modalities in the left T3 dermatome, loss of pain and temperature sensation from T4 downwards on the right side and loss of vibration and light touch from T4 downwards on the left side. Where is the lesion?
A. Left side of the T3 cord segment
B. Left side of the T4 cord segment
C. Right side of the T4 cord segment
A. Left side of the T3 cord segment
Rationale: This is Brown Sequard syndrome caused by cord hemisection. If the left T4 segment were destroyed you would see a similar pattern, but the T4 dermatome would lose all modalities. If the right half of the cord was affected then you would see right sided loss of dorsal column modalities and left sided loss of spinothalamic modalities (below the lesion)
A patient who was involved in a road traffic accident describes how he felt no pain, despite the fact that his leg had been crushed. What is a feasible neurophysiological mechanism for this?
A. Destruction of all of the nerves supplying his lower limb
B. Increased activity of enkephalinergic neurones in the spinal cord
C. Inhibition of the somatosensory cortex
Increased activity of enkephalinergic neurones in the spinal cord
This is caused by activation of descending analgesic systems from the PAG and nucleus raphe magnus. Destruction of peripheral nerves often leads to increased sensations due to ectopic action potentials in first order neurones. Inhibition of the somatosensory cortex is not a major mechanism here.
A patient has bilateral loss of temperature and pain sensation in the C6, C7 and C8 dermatomes. They have no other neurological signs. What is the most likely reason for this?
A. Bilateral thalamic tumours
B. Complete cord transection at C5
C. Syringomyelia affecting the C6-C8 cord segments
C. Syringomyelia affecting the C6-C8 cord segments
Rationale: Symmetrical signs are typically caused either by systemic or midline lesions. Bilateral thalamic tumours would be extremely unlikely and affect multiple modalities beyond the spinothalamic system. Complete cord transection would cause neurology in all systems below the lesion.
A patient has loss of all sensory modalities confined to the medial surface of the upper limb including the medial surface of the hand. Where is the lesion most likely to be?
A. The contralateral thalamus
B. The ipsilateral C5 spinal cord segment
C. The ipsilateral C8 spinal nerve
The ipsilateral C8 spinal nerve
Rationale: I should have specified a side here (it is unilateral). Hence, this is a dermatomal pattern consistent with compression of a spinal nerve at C8. The C5 segment supplies a completely different region. A thalamic lesion would cause effects in a much bigger area, not confined to a dermatome.
At what point do second order neurones of the spinothalamic system decussate?
A. At the level of entry of first order neurones
B. In the corona radiata
C. In the medulla
At the level of entry of first order neurones
Second order neurones in DC-ML system decussate in the medulla. There is no decussation in the corona radiata
Vibration and two-point discrimination are carried in which pathways running through the cord?
A. Dorsal column
B. Dorsal spinocerebellar tract
C. Spinothalamic tract
Dorsal column
In the dorsal-column medial lemniscus system first order neurones ascend the cord through which white matter region?
A. Dorsal funiculus
B. Lateral funiculus
C. Ventral funiculus
Dorsal funiculus
The lateral funiculus contains tracts such as the corticospinal and spinothalamic whereas the ventral funiculus contains the ventral corticospinal tract and a number of other small print pathways
Cell bodies of primary sensory neurones can be found in which structures?
A. Dorsal root ganglia
B. Parasympathetic ganglia
C. Sympathetic ganglia
Dorsal root ganglia
medulla mickey mouse
cerebral peduncles = ventral= motor
The raphe nuclei produce which neurotransmitter?
A. 5-HT (serotonin)
B. Dopamine
C. Noradrenaline §
A. 5-HT (serotonin)
Rationale: Dopamine is produced by regions such as substantia nigra. Noradrenaline is produced by regions such as the locus coeruleus
A tumour at the level of the interventricular foramen might lead to dilatation of which structures?
A. Fourth ventricle
B. Lateral ventricles
C. Third ventricle
B. Lateral ventricle
Rationale: The lateral ventricles drain to the interventricular foramen before entering the third ventricle.
The third ventricle drains directly into which structure?
A. The central canal of the spinal cord
B. The cerebral aqueduct
C. The fourth ventricle
B. The cerebral aqueduct
Rationale: From the aqueduct CSF then goes to the fourth ventricle. The central canal of the cord emanates from the fourth ventricle and contains an insignificant amount of CSF
Which part of the brainstem lies at the level of the tentorium cerebelli?
A. Medulla B. Midbrain C. Pons
B. midbrain
Rationale: The midbrain sits in the ‘tentorial notch’ and can be compressed if the uncus of the temporal lobe herniates into the posterior fossa
So-called ‘bridging veins’ traverse which space?
A. The extradural space
B. The subarachnoid space
C. The subdural space
C. The subdural space
Rationale: The extradural space contain branches of the middle meningeal artery (rupture can lead to extradural haemorrhage). The subarachnoid space contains important arteries to the brain tissue itself (rupture can lead to subarachnoid haemorrhage)
In the midbrain, which large white matter structures connect the cerebral hemispheres to the brainstem?
A. Cerebellar peduncles
B. Crus cerebri (cerebral peduncles)
C. Superior colliculi
B. Crus cerebri (cerebral peduncles)
Rationale: An alternative name for this is the cerebral peduncles. The cerebellar peduncles attach the cerebellum to the brainstem. The superior colliculi are features of the dorsal midbrain and deal with reflex actions to visual stimuli
The falx cerebri is composed of which meningeal layer?
A. Arachnoid
B. Meningeal dura
C. Periosteal dura
B. Meningeal dura
Rationale: In the midline (sagittal plane) the meningeal dura separates from the periosteal layer and dips down between the hemispheres to form the falx. Periosteal dura is adhered directly to the inner table of the skull. Arachnoid sits deep to the meningeal dura
An important source of dopamine for the motor system can be found in which structure?
A. The basal ganglia
B. The substantia nigra
C. The thalamus
B. The substantia nigra
Rationale: The substantia nigra resides in the midbrain (Mickey mouse’s eyebrows). The thalamus is an important sensory relay centre. The basal ganglia primarily contain inhibitory transmitters (but of course receive dopaminergic inputs from the SNc)
Which of the following is an excitatory neurotransmitter?
A. GABA B. Glutamate C. Glycine
B. Glutamate
Rationale: Glutamate is the most common excitatory transmitter in the CNS. GABA is the most common inhibitory transmitter in the CNS. Glycine is inhibitory and has an important role in ‘paralysing’ lower motor neurones during REM sleep
Which cell type can assume a macrophage-like appearance when activated?
A. Astrocytes B. Microglia C. Oligodendrocytes
Rationale: Microglia are an immune-type cell and oligodendrocytes myelinate CNS
Which cell type is primarily responsible for maintenance of the bloodbrain barrier? A. Astrocytes B. Microglia C. Oligodendrocytes
A
Rationale: Microglia are an immune-type cell and oligodendrocytes myelinate CNS axons
Amaurosis fugax (like curtains coming down) is a condition that is frequently caused by blockage of which artery?
A.Central retinal artery
B. Internal carotid artery
C. Thalamoperforator arteries
A.Central retinal artery
Rationale: This is transient blindness due to hypoxia in the retina. Occlusion of the internal carotid would cause widespread effects. Thalamoperforator arteries re branches of the posterior cerebral artery that supply the thalamus
In addition to the cerebellum, which structure does the superior cerebellar artery also supply?
A. Midbrain
B. Pons
C. Thalamus.
midbrain
Rationale: The midbrain is supplied by the SCA on its way to the cerebellum. The pons is supplied by pontine branches from the basilar artery. The thalamus receives blood supply from the thalamoperforator branches of the PCA
Thalamoperformator arteries are branches of which main artery?
A. Anterior cerebral
B. Middle cerebral
C. Posterior cerebral
C
Rationale: The middle cerebral arteries give off similar branches known as the lenticulostriate arteries, supplying the basal ganglia and internal capsule
Which brain region is supplied by the middle cerebral artery?
A. Inferior surface of the temporal lobes
B. Lateral surface of the frontal and parietal lobes
C. Medial surface of the frontal and parietal lobes
B. Lateral surface of the frontal and parietal lobes
Rationale: The inferior temporal lobe is supplied by the posterior cerebral artery. The medial frontal and parietal lobe is supplied by the anterior cerebral artery.
Internuclear ophthalmoplegia can be caused by damage to which pathway?
A. Medial forebrain bundle
B. Medial lemniscus
C. Medial longitudinal fasciculus
C. Medial longitudinal fasciculus
Rationale: The MLF helps to yoke eye movements together (and integrate input from the vestibular system). The medial forebrain bundle is a pathway relating to the hypothalamus (don’t worry about this). The medial lemniscus contains decussating second order sensory fibres in the DCML system
Photoreceptor cells synapse with which retinal cell type predominantly?
A.Amacrine
B. Bipolar cells
C. Ganglion cells
Bipolar
Rationale: Amacrine cells are a type of ‘horizontal’ interneurone. Ganglion cells receive inputs from bipolar cells and project to the LGN. Bipolar cells can be thought of as the first order sensory neurones of the visual system
Which of the following is a feature of the accommodation reflex?
A. Divergence of the eyes
B. Lens thickening
C. Pupillary dilatation
lens thickening
Rationale: The lens thicken to bend light rays more so that near objects stay in focus. The pupil normally constricts during accommodation (to help maintain focus). They eyes normally converge in accommodation
Homonymous superior quadrantanopia is most commonly seen in lesions to which part of the visual pathway?
A. Lateral geniculate nucleus
B. Meyer’s loop
C. Visual cortex
B. Meyer’s loop
Rationale: Meyer’s loop (inferior optic radiation) contains fibres from the contralateral superior quarter of the field. This leads to a ‘pie in the sky’ defect. LGN lesions would cause a contralateral homonymous hemianopia. Visual cortex lesions would cause a contralateral homonymous hemianopia, possibly with macular sparing
Destruction of the optic tract is rare. What would be the consequence of compression of the right optic tract?
A. Left homonymous hemianopia with macular sparing
B. Left homonymous hemianopia without macular sparing
C. Left superior homonymous quadrantanopia
B. Left homonymous hemianopia without macular sparing
Rationale: Macular sparing is a feature of (vascular) lesions of the occipital lobe. A right sided lesion would cause a left sided field defect. Superior quadrantanopias are caused by destruction of the inferior optic radiation (Meyer’s loop)
A patient has a tumour arising from the right cavernous sinus and invading medially towards the optic chiasm. Which visual field defect might this result in?
A. Binasal hemianopia
B. Right homonymous hemianopia
C. Right nasal hemianopia
C. Right nasal hemianopia
Rationale: If the tumour erodes medially it will destroy fibres from the temporal retina of the right eye. The right temporal retina subserves the nasal field (of the right eye). Hence there will be a unilateral right nasal hemianopia. Binasal hemianopia is extremely rare and would be caused by a lesion eroding into both lateral aspects of the chiasm. A right homonymous hemianopia would be caused by a lesion from the left optic tract or posterior to this
A patient suffers from sudden onset of complete monocular blindness. Which is the most likely site of a lesion?
A. Lateral geniculate nucleus
B. Optic chiasm
C. Optic nerve
C. Optic nerve
Rationale: Lesions at the chiasm or lateral geniculate would cause hemi field loss. Only a lesion in the optic nerve (or eye itself) could cause complete monocular blindness
The lateral geniculate nucleus projects to which lobe?
A. Frontal lobe B. Occipital lobe C. Temporal lobe
B
Rationale: The LGN is part of the thalamus, relaying visual information from the optic tracts to the visual cortex. The medial geniculate nucleus is involved with auditory processing
In which part of the retina are cones particularly common? A. Macula B. Optic disc C. Peripheral retina
A
Rationale: Cones are responsible for high acuity, colour vision and are positioned centrally at high density. The optic disc has no photoreceptors. The peripheral retina has predominantly rods.
A patient complains of a transient loss of vision in one eye that resolved after four hours. Blockage of which vessel caused this?
A. Internal carotid artery B. Ophthalmic artery C. Posterior cerebral artery
B
Rationale: This is a typical story describing amaurosis fugax, which is transient blindness caused by blockage of the ophthalmic artery
